View Full Version : Mental ray memory problem and part rendering

07 July 2006, 05:02 PM
Hello Everybodies.

I had to render a huge image (8154x6120 pixels).
But i have a memory crash with mental ray. That's makes me crazy :sad:

I have a dualcore PentiumD 930 with 2Gb Ram DDR2 and 24Gb free space on hard drive, under Windows XP.
The scene have 1,139,804 polygons.

I tried a lot of things.
- put memory limits to low value (300, 400, 800, 1000mb)
- put in large bsp mode with low size and high depth.
- check conserve memory, use placeholder objects, use mental ray map manager.

Mental ray crashes with all but with "conserve memory" mental ray calculate a great black image :sad: with message "cannot allocate buffer file..." (or something like that) in a temp directory. But I have 24Gb free on the hard drive.

On all crashes, mental ray tell me the same number of octet he can't allocate.

I want to calculate parts of the image by use region mode but mental ray crashes too. That's weird or i'am stupid :)

Someone have a solution to make mental ray calculate and save me or tell me a way to calculate parts of image without crash.

Please, i need your help.

Thank you a lot for your help. ;)

07 July 2006, 05:40 PM
Have you tried using backburner and "render to strips" (something like that)...

07 July 2006, 05:46 PM
Hello Myliobatidae

Thank you for your trick.
I test it now.

I test the render by hidding the half of objects in the scene (expected mental ray calculate less of polygons) and he crash too with the same number of Kilobytes he can't allocate.

Have you and idea about that ?

07 July 2006, 05:53 PM
I test your trick Myliobatidae but it crash too.
It says "renderer error : initializing renderer : render failed"

I think i must calculate half of final size and stretch it :sad:
That's bad.

Someone have a solution ?

07 July 2006, 12:33 AM
Have you tried activated the Bitmap Pager function in Customize>Preferences>Renderer?

It's worked for me when rendering billboard size images before.

Here's the info from Maxhelp:

Bitmap Pager group

The Bitmap Pager can help with the rendering of scenes that have very large textures, a large number of textures, or when rendering a high-resolution image.

Tip: You can access a Bitmap Pager Statistics dialog (bitmap_page_statistics_dialog.html) with useful pager information such as memory usage: Go to Customize menu > Customize User Interface, find the Bitmap Pager Statistics item in the Main UI list, and then assign it as a keyboard shortcut or other UI element.

On—When turned on, the software creates a series of temporary “page” files on the drive where it is installed for use in rendering bitmaps.

Page Size (kB)—Sets the size of the bitmap page. If textures are smaller than the page size, the system allocates only the memory required.

Bitmap Size Threshold (kB)—Sets the minimum size (in kilobytes) that a bitmap must be in order to be paged.

Memory Pool (kB)—Controls the amount of memory used by the pager. All pages remain in memory until this limit is reached. When the limit is reached, the pager begins saving pages to disk. Pages that are not frequently used are paged out; more frequently used pages are kept in memory."

One last crude technique is to render region a small area of your scene, and then repeat that for another part of the scene with a slight overlap on the first image, and put all the images back together in Photoshop. Not great, but sometimes it's the only way...

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07 July 2006, 12:33 AM
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